This review by Krishna K. Niyogi revisits the topic of photoprotection in plants and green algae, focusing on the genetic and molecular approaches that have recently provided new insights into the mechanisms of photoprotection. The review highlights several key processes, including adjustment of light-harvesting antenna size, thermal dissipation of excess absorbed light energy, alternative electron transport pathways, chloroplast antioxidant systems, and repair of photosystem II (PS II) damage. The generation of reactive oxygen species (ROS) during photosynthesis poses a significant threat to the photosynthetic apparatus, leading to photo-oxidative damage. To counteract this, plants have evolved multiple photoprotective mechanisms. These include the regulation of light-harvesting antenna size to balance light absorption and utilization, thermal dissipation through the xanthophyll cycle, alternative electron transport pathways such as photorespiration and the water-water cycle, and the presence of antioxidant molecules and enzymes like carotenoids, tocopherols, ascorbate, and glutathione. The review also discusses the role of specific genes and proteins in these processes, emphasizing the importance of genetic and molecular approaches in understanding and enhancing photoprotection.This review by Krishna K. Niyogi revisits the topic of photoprotection in plants and green algae, focusing on the genetic and molecular approaches that have recently provided new insights into the mechanisms of photoprotection. The review highlights several key processes, including adjustment of light-harvesting antenna size, thermal dissipation of excess absorbed light energy, alternative electron transport pathways, chloroplast antioxidant systems, and repair of photosystem II (PS II) damage. The generation of reactive oxygen species (ROS) during photosynthesis poses a significant threat to the photosynthetic apparatus, leading to photo-oxidative damage. To counteract this, plants have evolved multiple photoprotective mechanisms. These include the regulation of light-harvesting antenna size to balance light absorption and utilization, thermal dissipation through the xanthophyll cycle, alternative electron transport pathways such as photorespiration and the water-water cycle, and the presence of antioxidant molecules and enzymes like carotenoids, tocopherols, ascorbate, and glutathione. The review also discusses the role of specific genes and proteins in these processes, emphasizing the importance of genetic and molecular approaches in understanding and enhancing photoprotection.